That’s not always true. I run into this on boats alot. If you have them both connected together and one is fully charged and the other is not, the regulator will not know that the other batt needs more amps unless the batt’s are connected to the alt by them selves. It only see's the fuller charged batt. Eventually the fact that they are connected all the time, the full batt will bleed off amps to the lower charged batt. This is a process that could take several days depending. I recently had this problem on my boat with 2 batts, one was fully charged and the other was near dead. My problem was I use a switch to select the batt I want to use. This switch has the option of selecting both at the same time. I thought if I ran the boat for a couple of hours with both batts on, this way it would charge both but I read now that it won't not to mention my anchor batt died in a matter of a couple of hours running the radio. It charges the batt that is fuller and then thinks it's job is done and pulls back amps. My boat uses an alt just the same as a car by the way. If you are going to leave both always connected at the same time all the time, make sure both have a lead from the alt this will help the chances that both batts will be charged. Just make sure they are both fully charged when you install them and are the same size batts, this will help make sure they both receive the same amount of charging. Also make sure that both batt's have a lead to the ACC so you are not trying to draw from one batt to another. Drawing from one batt to another is really inefficient because it will deplete the first batt closest to the ACC post as they are wired before drawing on the batt further away. Hope this makes sense lol.
Dual Battery Kit
- Thread starter sparg93
- Start date
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That’s not always true. I run into this on boats alot. If you have them both connected together and one is fully charged and the other is not, the regulator will not know that the other batt needs more amps unless the batt’s are connected to the alt by them selves. It only see's the fuller charged batt. Eventually the fact that they are connected all the time, the full batt will bleed off amps to the lower charged batt. This is a process that could take several days depending. I recently had this problem on my boat with 2 batts, one was fully charged and the other was near dead. My problem was I use a switch to select the batt I want to use. This switch has the option of selecting both at the same time. I thought if I ran the boat for a couple of hours with both batts on, this way it would charge both but I read now that it won't not to mention my anchor batt died in a matter of a couple of hours running the radio. It charges the batt that is fuller and then thinks it's job is done and pulls back amps. My boat uses an alt just the same as a car by the way. If you are going to leave both always connected at the same time all the time, make sure both have a lead from the alt this will help the chances that both batts will be charged. Just make sure they are both fully charged when you install them and are the same size batts, this will help make sure they both receive the same amount of charging. Also make sure that both batt's have a lead to the ACC so you are not trying to draw from one batt to another. Drawing from one batt to another is really inefficient because it will deplete the first batt closest to the ACC post as they are wired before drawing on the batt further away. Hope this makes sense lol.
SunlitComet
OBS Jedi-Do Good
The dealer still sells all the oem parts for the second tray I think. I estimated it to be about $90 locally at my dealer. battery extra.
---------- Post added at 02:48 PM ---------- Previous post was at 02:40 PM ----------
Verify your alt type if it is A delco cs or cs-d type it will not work properly. that store has others that will. If you want something with some smarts to it you can try this:
http://www.summitracing.com/parts/PRF-40120/
It can actually combine the two batteries if main is low to help starting as well as smartly charge them. Cost some bucks though.
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blueflamed03
Supporting Member
for that wiring harness, and new battery, makes the D3100 look more pleasing. 
I like the idea of that Painless product...I wonder how well it works??
Have you heard anyone that uses it and their feedback?
---------- Post added at 06:33 PM ---------- Previous post was at 06:03 PM ----------
You certainly have a point there Blue!!
Have you heard anyone that uses it and their feedback?
---------- Post added at 06:33 PM ---------- Previous post was at 06:03 PM ----------
You certainly have a point there Blue!!
raptorforme93
Full Access Member
Do you have to have the same batteries or can you use two different batteries? I have an extra battery that is still good and would like to use it if possible. Dual batteries seems to be more complicated than it sounds. haha
SunlitComet
OBS Jedi-Do Good
Never see any reviews for probably all there products but when it comes to upgrades in the magazines they are always there. It one of those companies that just does everything right IMO. I will be using one later this year.
If the battery is similiar in use it should be fine. Throw a good fusing circuit between it and the alt still.
If the battery is similiar in use it should be fine. Throw a good fusing circuit between it and the alt still.
raptorforme93
Full Access Member
You mean similar in use as in both of them being car batteries? Or similar in use as in they are the same size and have the same specs?
SunlitComet
OBS Jedi-Do Good
mostly electrical specs as I can not say for certain that you can put a car or deep cycle battery paired with say a much smaller battery without somekind of power regulation but car and/or deep cycles with the same voltage and say close reserve capacities or AH ratings should be no problem. I was just concerned about pushing to many amps into a small battery that can't handle accepting to many charging amps at once.
rdhenderson
Member
I just got done installing a dual battery set-up in my 96 and did a Big 3 upgrade while I was at it. I put together a little progressive write-up and posted it on a thread. The isolator I installed was a unit from Surepower. I have no clue of how to post a link to that thread on here so you may want to just look up my profile to get access to it.
